With the development in miniaturization and high-integration of semiconductor elements, strong requirement arises for reduction in voltage of a power source which is used for an integrated circuit such as a semiconductor memory device or an SoC. Accordingly, various reference voltage generating circuits have been developed which operate at a low power supply voltage and which generate a voltage serving as a reference voltage for use of an interior of an integrated circuit.
Japanese Patent Application Publication (Kokai) No. 11-45125 discloses a bandgap reference circuit serving as a reference voltage generating circuit. The bandgap reference circuit includes a bandgap reference section and a comparator. The bandgap reference section can operate at a power supply voltage being as low as about one Volt. However, the comparator does not operate at a power supply voltage of 1.5 Volt or less, for example.
Consequently, the bandgap reference circuit as a whole does not operate at a low power supply voltage of 1.5 Volt or less, for example. When the threshold voltage of a transistor constituting the comparator is lowered to operate the comparator at a low voltage, leak current is increased, which increases power consumption.